JCBC-257 : Added default values of Hash Algo and Failure Mode when null.

Change-Id: Id6525bbc651168ff57d93992fb1e79f802e8f35b
Reviewed-on: http://review.couchbase.org/24989
Tested-by: Deepti Dawar <deepti.dawar@globallogic.com>
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>